Here are some useful links for building your child's understanding of Maths. There is step-by-step guidance and is broken down into different areas of learning.
https://www.mathematicsmastery.org/wp-content/uploads/2020/03/Parent_Maths_Y1_W1-2.pdf
https://www.mathematicsmastery.org/wp-content/uploads/2020/03/Parent_Maths_Y1_W3-5.pdf